The present invention relates to a stern tube seal device.
A stern tube seal device of this kind heretofore used is designed so that a mechanical seal is singly incorporated. In the prior art device of this kind, the mechanical seal directly seals sea water and lubricating oil (bearing oil), and therefore, there is a danger in that a sliding surface is damaged by slurry contained in sea water, thus making it difficult to maintain a stabilized sealing performance.